Vehicle brake



July 17, 1928.

B. A. LAREVA VEIGLE BRAKE File@ March 25, 1.927

vPatented July 17, 19287.

ii i 'rs sr y s BERT A, LAREVA, OF SPOKAN, WASHIING'ITON. 4

VEHICLE BRAKE.

Appiieauon filed Marcil 23, 1927. serial No. 177.568.

My present invention relates to improvements in vehicle brakes of theI luid pressure type of internal resistance, Vemploying reciprocatiii'g pistons in communicating cylinders or chambers. The fluid pressure brakes while applicable for use with automotive vehicles of various types, are especially adapted for use with automotive trucks and other heavy duty vehicles whereV a positive braking system is required with low operating expense. p

rlChe braking system includes a pumping mechanism comprising acrank shaft thatis connected, as by sprocket chain or other gearing with the propeller shaft 'of the vehicle, and a clutch mechanism is provided on the propeller sha-it whereby the normally idle pumping mechanism is c-oupled with and driven 'from the propeller shaltA to supply the internal resistance of lluid pressure to retard or prevent the operation of the propeller shaft. In connection with the operating device of the clutch mechanism means are provided for controlling and operating a control valve for the fluid pressure brake, as will hereinafter be more specifically pointed out and claimed.

In the accompanying drawings I have illustrated one completer example of the physical embodiment of Vmy invention wherein the parts are shown and combined and arranged according` to the best inode I have thus far devised for the practical application of the principles ot my invention.

Figure 1 is a plan view of the parts of an automotive vehicle that are necessary to illustrate the general assembly and arrangement of parts of my invention.

Figure 2 is a view of an elevation of the fluid brake device showing the control valve and pipes of the fluid circulation system connected with two cylinders or chambers. Figure 3 is a detail sectional view of the pump or brake chambers7 showing" the pistons, one of which is in section7 the crank shaft, etc.

Figure 4 is a bottom plan view of a piston valve-head in its cylinder.

Figure 5 is an enlarged detail sectional view oi" the'valve-head of one of the pistons.

Figure 6 is a detail sectional view ot one of the pipes showingthe pressure regulatingA valve to secure resiliency in the circulation system and relieve undue strains in the application of braking power, as at line 6-6 Fig. 2.

Figure 7 is a perspective view, at the end of a piston showing the seat for the valvehead. t Y

. In order that the general assembly and arrangement of parts may readily be understood I have indicated in Figure 1 chassis l ot an'autoinotive truck and the usual longitudinally disposed propeller shaft 2. The braking device which is indicated as a' whole by the numeral 3 is located at one side of the propeller shaft and of course supported from the chassis. Suitable gearing, as a sprocket chain l and sprocket wheel 5 are employed to drive the sprocket wheel 5 on the crank shaft 12, from the propeller shalt 2, and in connection with this drive gearing for the braking mechanism I employ a clutch device 6 of the friction type on the propeller shaft. The clutch is controlled and operated from the pedal or lever 7. which is located in position readily acces-l sible foi the driver of the truck, and the connecting rod V8 extends rearwardly to the clutch yoke 9. A spring 10 is utilized to hold the clutch operating mechanism inopen position and to return the clutch to that position after an application of the brakes. An operating lever 11 for the brake 3 is connected to the control valve 13 and this lever is operated simultaneously with the clutch yoke 9 thereby positioning the vparts to transmit power from the propeller sh'ait to the crank shaft and arranging for the internal fluid pressure or internal resistance of the brakes to retard or stop the propeller shaft.

The crank shaft' is jo'urnaled in bearings iii the crank case 14 and the latter is fashioned with a pair of cylindersl or chambers 15 and 16 in which thehollow pistons 17 'and 18 reciprocate idly vwhen the control` valve 13 is open,`but which form compressors for the oil or other fluid in the cylinders when the control valve is partially or wholly closed to prevent circulation of the oil .in the` braking system. The pistons are connected as usual to the crank shaft by rods 19 and each piston is fashioned with open ends so that theV oil, in circulation, may pass through the pistons in one direction on the idle stroke of the compressor piston.

At one end each open-end piston is provided with a pair of concentric rings or seats 20 and 21 and a'central hub or hearing 22, the latter for the slidable stem .23 of the grooved valve-head 24 which is held normally on the seats or rings20 and 21 Lil by the spring 25. On the downor working stroke of the piston the valve head is closed on its seats and the fluid is compressed to perform the functions of a brake, while on u the up or idle stroke of the piston the spring` rretained valve-head is opened by fluid presressure ma1v be e ualizcd in the chambers Y J' or cylinders and throughout the pipes 26 and 27. Check valves 3 and 3l which open away from the ressure s'zde ot'r the pistons are located in t e pipes to insure one-way circulationof the oil, and a regulating valve 32 which is opened' against the tension of spring 33, and which opens in the opposite direction to that of the check valves, is located in the casing 340iE the pipe 2T. As previously stated, when valve 13 is open the oil is free to circulate, but when the valve is partially closed, its circulation is retarded, and a' complete closure of `theyalve and stoppage of circulation, applies the brake to stop revolution of the propeller shaft.

Having' thus fully described my invention,

friction clutch., a sprocket wheel'and chain` connecting said wheels,v a pedal actuatedlcontrol lever and valve for Athe iiuid braking system, operating means for the clutch and means for normally holding the clutch open, and means connectin` the clutch operating means with the control lever.

2. VIn a lluid braking systemthe combination with a pair ol cylinders, a crank shaft and pistons connected to the shaft and having open ends, ol" spring pressed Valve-heads to close said pistons on their working strokes, la circulation' pipe connected atjthe opposite ends of each cylinder and check `valves in said pipes, a control valve in one E said pipes, and a pressure regula'ting,` Valve in the other of said pipes, and a cross pipe connectingsaid circulation pipes. y

In testimony whereoflaiiix my signature.

v BERT A. LAREVA. 

